Straw bale spec homes now for sale in the UK

It would take an extraordinary force of nature to blow one of these straw-stuffed brick abodes down.

Each of the seven brick-clad, straw-insulated homes in Bristol sports an interior 'truth window' to showcase what's inside of the walls. (Photo: University of Bath)

Mention homes built from straw in the United Kingdom and, depending on what type of company that you’re in, you’ll be met with either a quizzical glare, an exaggerated sigh or a round of hammy huffing and puffing. It comes with the territory.

While straw bale home construction has been around for ages and boasts numerous advantages over conventional building methods (more on that in a bit), its associations aren’t always propitious. Some immediately think of Middle Earth-inspired dwellings that fall under the code-breaking and/or clandestine category. Others might associate straw bales with illicit faux castles or garden toilets. Less reported on are straw bale homes that work.

Straw bales, however, are the driving force behind a new housing development on St. Bernard's Road in the Shirehampton district of Bristol that puts to rest any misconceptions about building with an agricultural byproduct associated with animal bedding. The development aims to, well, blow straw bale construction into the mainstream as a commercially viable and environmentally friendly alternative to conventional home building.

Built on spec and incorporating innovative technology developed by researchers at the University of Bath in partnership with straw-centric architecture firm ModCell, the seven Bristol residences are the first ever straw bale abodes to hit the open market in the United Kingdom.

From the outside, the brick-clad townhomes appear to be nothing all that special — just another new housing development that politely blends into Bristol's suburban landscape. But thanks to the homes’ straw-stuffed walls that provide two times the amount of insulation required by British building code, homeowners will enjoy significant energy savings including heating bills that are a whopping 90 percent lower than the brick-built neighbors. Added bonus: the homes are slightly more affordable than their non-straw-walled kin.

And what about fire, severe weather and threats of a lupine nature? Do straw bale homes stand resilient?

Pete Walker, head of the Department of Architecture & Civil Engineering at the University of Bath, explains to the Guardian that straw houses are pretty much as tough — and fire-safe — as they come:

Over the past three years of research we have looked at various aspects of the performance of straw. Two that particularly come to mind as concerns or apprehension from potential users of straw are fire-resistance and weather-resistance.

We have conducted a number of fire tests that have demonstrated that fire resistance from straw bale construction is remarkably good and better than many contemporary forms of construction.

In terms of durability, we have undertaken laboratory tests and undertaken monitoring of existing buildings and we have also done accelerated weather tests. The results of all these tests suggest that straw is a very durable construction solution.

While the seven new homes are not fully prefab, the timber-framed, straw bale-filled walls of the homes are indeed prefabricated off-site by Bristol-based ModCell using local straw. The company describes the wood-encased wall panels, each as thick as a standard straw bale, as being “the first products to make large-scale, carbon-negative building a commercial reality.”

In addition to superior energy savings, there are other environmental perks to using straw to insulate new homes. A little under 4 million metric tons of excess straw, the byproduct of wheat production, is generated in the U.K. each year. Instead of being left to waste, the straw could be easily used to help build much-needed affordable housing. According to Walker and his team, a three-bedroom house with a ModCell's engineered wall system requires about 7 metric tons of straw. Translation: there’s enough straw to go around to build over 500,000 energy-saving new homes across England.

It's also worth noting that as it grows, straw absorbs a large amount of carbon dioxide. In turn, homes built from straw could be considered carbon negative.

“The construction sector must reduce its energy consumption by 50 percent and its carbon emissions by 80 percent by 2050, so radical changes are needed to the way we approach house building,” Walker says. “As a construction material, straw is a low-cost and widely-available food co-product that offers real potential for ultra-low carbon housing throughout the U.K. Building with straw could be a critical point in our trajectory towards a low-carbon future.”

Now you may be wondering what the fun of living in a straw house is if it doesn’t look like a straw house. Aside from waving around ultra-low energy bills, how can one show off their super-cool straw house to friends and neighbors? As ModCell's Craig White reveals to BBC Victoria Gill, each of the new homes in Bristol comes equipped with a prominently placed interior “truth window” or "honesty panel"— a glazed wall cut-out that showcases the home’s unique innards. “We do that,” White explains, “because a lot of people don’t believe houses are made of straw.”